JP2000343883A - Knock type mechanical pencil - Google Patents

Abstract

PROBLEM TO BE SOLVED: To smoothly slide even when a circumferential protrusion is brought into contact with an inner surface of a barrel or a head crown by constituting the protrusion formed at a corner of a vertex in a curved surface at an intermediate part of the cylindrical portion of a knob, and disposing the protrusion at an inner surface side of a rear portion of the barrel. SOLUTION: A knob 15 covering an eraser 14 has a cylindrical portion 15A constituted of a pipe material made of a metal and a spherical decorative portion 15B fixed to a rear portion of the portion 15A. A circumferential protrusion 15C is raised from its inside at the intermediate part of the portion 15A, and formed at its vertex in a curved surface. The knob 15 is engaged with a rear outside 12D of an eraser support 12, and the protrusion 15C is disposed at an inside of an inner surface of the crown 9. With this constitution, even when the protrusion 15C of the knob 15 is brought into contact with an inner surface of the crown 9 made of a metal roughed on its surface by cutting, the knob 15 can be smoothly slid, thereby upgrading a knocking operation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanical pencil which pushes a chuck by pushing a knob to feed a lead.

[0002]

2. Description of the Related Art In a conventional knock mechanical pencil, a clearance between an inner surface of a rear portion of a barrel and an outer peripheral surface of a barrel of a knob is reduced in order to prevent a lead tank and a knob located in the barrel from swinging. Was composed.

[0003]

Therefore, when the lead tank is bent and mounted, or when the knob is fitted to the lead tank at an angle, the outer peripheral surface of the knob is rubbed against the inner surface of the rear part of the shaft cylinder. The problem that it became worse occurred.

[0004] It is an object of the present invention to provide a knock mechanical pencil that solves the above-mentioned problems.

[0005]

According to a first aspect of the present invention, there is provided a knock-type mechanical pencil which pushes a chuck by pushing a knob protruding from a rear end of a barrel to feed a lead. In the middle portion of the cylindrical portion, a circumferential protrusion having a curved top portion is formed, and the circumferential protrusion is positioned inside the rear inner surface of the shaft cylinder.

According to a second aspect of the present invention, a head cap is attached to a rear part of a barrel, and a knob protruding from a rear end of the head cap is pushed to advance a chuck to draw out a core. In the knock-type mechanical pencil, a circumferential projection having a curved corner at the top is formed in a middle portion of the tubular portion of the knob, and the circumferential projection is positioned inside the inner surface of the cap.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A knock mechanical pencil according to a first embodiment of the present invention will be described below with reference to FIG. Chuck 1;
A core tank 2 made of a synthetic resin pipe connected to a chuck 1 and a tightening ring 3 externally fitted to the head 1A of the chuck 1
The coupling 4 for receiving the tightening ring 3 and the spring 5 stretched between the coupling 4 and the core tank 2 constitute a mechanical part of a knock mechanical pencil. A wick 6 is housed in the wick tank 2.

A front hole 7A of the barrel 7 is formed so that the core tank 2 can be inserted therein. A clip 8 is integrally formed at the rear of the barrel 7, and a metal head is provided at the rear of the barrel 7. The crown 9 is fixed. The crown 9 is formed by cutting, and the rear part of the core tank 2 is inserted into the inner collar 9A of the crown 9 from the front in the longitudinal direction.

Further, the connecting member 4 is sandwiched between the front end of the barrel 7 and the inner stage 10A of the base 10 screwed to the front of the barrel 7. A base holder 11 made of an elastic body such as rubber for holding the core 6 with an appropriate force is incorporated in the base 10.

At the rear of the core tank 2, a front small diameter portion 12A of an eraser support 12 inserted from behind the shaft cylinder 7 is press-fitted, and an eraser support is provided by an outer flange 12B formed on the front small diameter portion 12A. 12 is firmly pressed and fixed to the core tank 2. Further, an eraser 14 provided with an eraser case 13 is fitted into the rear inner side 12C of the eraser support 12.

As shown in FIG. 2, the knob 15 covering the eraser 14 is a cylindrical portion 15A made of a metal pipe material.
And a spherical decorative portion 15B fixed to the rear portion of the cylindrical portion 15A, and a circumferential projection 15 is provided at an intermediate portion of the cylindrical portion 15A.
C is protruded from the inside. Moreover, the top of the circumferential protrusion 15C is formed into a curved surface. The knob 15 is fitted to the rear outer side 12D of the eraser support 12 so that the circumferential projection 15C is located inside the inner surface of the crown 9.

In the case of the first embodiment, even if the circumferential projection 15C of the knob 15 contacts the inner surface of the metal crown 9 whose surface is roughened by cutting, the knob 15 slides smoothly. The knocking operation can be performed satisfactorily.

FIG. 3 shows a second embodiment of the present invention. The same members as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted. A clip 108 is formed integrally with the rear part of the shaft cylinder 107. Further, as shown in FIG. 4, a metal knob 115 is formed by press molding, and the cylindrical portion 11 of the knob 115 is formed.
5A, the circumferential protrusion 115C is configured to protrude from the inside. In addition, the top of the circumferential protrusion 115C is formed flat, and corners located before and after the flat are formed in a curved surface.

The knob 115 is fitted to the rear outer side 12D of the eraser support 12, so that the circumferential projection 115C of the knob 115 is located inside the rear inner surface of the shaft cylinder 107.

In the case of the second embodiment, when the knob 115 slides back and forth, the corner of the circumferential protrusion 115C is formed into a curved surface, so that the circumferential protrusion 115C is The knob 115 can smoothly slide back and forth even if it comes into contact with the inner surface of the bracket, and the knocking operation can be performed well.

[0016]

The writing instrument member of the present invention described above has the following features.
Since the corner of the top of the circumferential projection formed in the middle of the knob cylinder is formed into a curved surface, even if the circumferential projection contacts the inner surface of the shaft cylinder or the crown, it slides smoothly. It is possible to obtain an effect that the knocking operation can be performed well.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a knock mechanical pencil according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the knob of the first embodiment.

FIG. 3 is a sectional view of a main part showing a knock mechanical pencil according to a second embodiment of the present invention.

FIG. 4 is a sectional view showing a knob according to a second embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 chuck 6 core 7 shaft cylinder 9 crown 15 knob 15A cylinder section of knob 15 15C circumferential projection of knob 15 107 shaft cylinder 115 knob 115A cylinder section of knob 115 115C circumferential projection of knob 115

Claims (4)

[Claims] 1. A knock-type mechanical pencil, in which a chuck is advanced by pushing a knob protruding from a rear end of a shaft cylinder to feed out a core, a circumference having a curved top surface at an intermediate portion of a cylinder portion of the knob. A knock-type mechanical pencil, wherein the mechanical projection is configured such that the circumferential projection is located inside a rear inner surface of the barrel. 2. A knock-type mechanical pencil in which a head crown is attached to a rear portion of a barrel and a knob protruding from the rear end of the head crown is pushed to advance a chuck to draw out a lead. A knock-type mechanical pencil, wherein a circular projection having a rounded top corner is formed, and the circular projection is positioned inside the inner surface of the crown. 3. The mechanical pencil according to claim 1, wherein the tubular portion of the knob is made of a metal pipe material and the circumferential projection is raised from the inside. 4. The knob has a tubular portion formed by press molding,
3. The mechanical pencil according to claim 1, wherein the circumferential projection is raised from the inside.